The importance of executive function (EF) in social, emotional, academic and career domains is well established. The goal of the proposed research is to investigate the association between language and EF abilities in school-age children with typical and atypical development. There are two separate lines of research that provide empirical support for the existence of a relationship between language and EF. First, research on bilingualism suggests that experience with two languages facilitates EF skills. Second, the disabilities literature has focused on whether dysfunction in executive control may be one of the factors underlying deficits associated with Specific Language Impairment (SLI) and Autism Spectrum Disorders (ASD). In both accounts, there is some conflicting evidence and both approaches are underspecified in terms of the particular components of EF and specific language functions that may be linked. The proposed project will bridge the bilingualism and the disorders literatures by examining the relationship between language and executive function in typically-developing bilingual and monolingual children, children with SLI, and children with ASD. The theoretical motivation for exploring the relationship between language and EF stems from a leading developmental theory of executive control proposed by Zelazo and colleagues. By investigating EF performance across groups with varying language abilities we aim to test a critical assumption of this model related to the use of language to manage executive control. A total of 160 children (40 per group) will participate in four studies designed to address the following three specific aims: 1) Compare the performance of bilingual, monolingual, SLI, and ASD groups matched on age and nonverbal cognition on a range of EF measures; 2) Examine the concurrent and longitudinal relationship between specific components of EF and language knowledge, processing, and learning across the groups; and 3) Directly assess the role of verbal mediation in EF across these groups with typical and atypical language abilities. The proposed project represents an innovative approach to establishing a comprehensive conceptual framework that spans the extent of individual variation from enhanced abilities in language/EF to impairments in language/EF. Findings from this project also have potential implications for targeted interventions for children with language disorders.